Free foil flow control device

ABSTRACT

The invention provides a fluid flow control valve having a chamber with one inlet and at least one outlet and a movable plate or foil movable within the chamber to open and close the outlet or outlets. Control means communicate with the chamber to actuate the plate or foil and said control means may be pneumatic, hydraulic, electrical or mechanical. Two or more of the control valves can be coupled together to form a valve assembly.

I I United States Patent 1191 1111 3,709,244

Zadow et al. [451 Jan. 9, 1973 54] FREE FOIL FLOW CONTROL DEVICE 3,030,930 4/1962 Gratzmuller ..91/42o x 3 370 601 2/1968 Nevulis ....91/420 X [75] Inventors: Hanm Zadow; Herbert Zadow, both l kwrw 1,304,286 5/1919 Emden .91/420 X I [22] Filed; Nov. 4, 1970 Primary Examiner-Robert G. Nilson Att B't fld&L' 1 pp No: 41 2p orney r1e en e evme [30] Foreign Application Priority Data 57 ABSTRACT q fiiLBf The invention provides a fluid flow control valve hav- 52 U.S. c1. ..l37/l06, 91/420, 137/6255 g a chamber with one inlet and at least n outlet [51] Int. Cl ..Fl6k 31/12 and a movable pl of foil movable within the [58] Field of Search....l37ll02, 106, 596.14, 596.18; chamber to open and close the outlet or outlets. Con- 91/420 trol means communicate with the chamber to actuate the plate or foil and said control means may be pneu- [56] References Cited matic, hydraulic, electrical or mechanical. Two or more of the control valves can be coupled together to form a valve assembly 3,039,491 6/1962 Raney ..91/420 UX 3,566,903 3/1971 Honeycutt ..l37/106 n m'wlng Figures 30 53) 31 I/ II/ PATENTEUJAN 91975 3,709,2 4

SHEET 3 0F 9 A r m was INVENTORS:

PATENTED JAN 9 I975 SHEET u 0F 9 M m F INVENTORS:

PATENTED JAN 9 I975 SHEET 5 OF 9 8. 2 S Q Mm v m E m Q m:

3 m m. 3 87 Q, Q, Nwmw E 8. mm. M f N a. W A 2 N mm. 5 no No m9 me A mm aw ow @9 m9 1 l N Q B 257 @2 mm B\ 6 $69 09 E A rroxneis FREE FOIL FLOW CONTROL DEVICE This invention relates to fluid flow control valves.

Such valves may be used for controlling the flow of liquid or gaseous fluids so that fluid supplied through an inlet port is delivered out of one outlet port intermittently, or from each of two outlet ports alternately. A valve of this kind can be used to generate alternating flows of fluid or to control reciprocating movements of for example pistons in cylinders and fluid motors.

The most suitable device for this purpose available at present is the hand or power-operated spool valve which directs fluid to the various ports in accordance with the position of a cylinder provided with annular grooves, said cylinder or spool being movable in the axial direction inside a bore in a housing. In order to ensure easy movability at the same time avoiding excessive leakage between the grooves of the spool sliding in the bore of the housing it is necessary to manufacture both one spool and one bore within close limits of tolerance with respect to circularity, straightness in the axial direction, and also to physical dimensions. Because, however, of the clearance required between spool and bore, valve failures are sometimes caused by the entry of solid particles into this narrow gap, by which further movement of the spool may be prevented. Other shortcomings of spool valves are that contact between spool and bore causes wear by friction and that speed and frequency of operation is limited by the inertia due to the comparatively large mass of the spool and its operating components.

According to the present invention a fluid flow control valve comprises a housing having a chamber therein, an inlet port leading into said chamber and at least one outlet port leading from said chamber and a valve member located in said chamber in the form of at least one movable plate, the or each plate being movable between two opposed walls of the chamber in response to control means, said inlet port being located so that it is not obstructed by the or each plate in any position thereof and the or each outlet port being located so as to be obstructed by the or each plate in one position thereof and unobstructed in another position of the or each plate.

A valve of this kind may be used in a control device having several such valves.

The chamber may be cylindrical, or of wedge shape cross-section having oblong or circular side walls. The or each valve plate may be a thin circular disc, or be for example, oblong to conform to the shape of the side walls of the chamber.

The valve may have an outlet port situated in one side wall, or two outlet ports situated in opposite side walls. The inlet port may be in the circumferential wall.

In order that the invention may be well understood there will be described some general lay-outs and embodiments thereof, given, by way of example only with reference to the accompanying drawings in which:

FIG. 1 shows schematically one embodiment of a valve assembly incorporating three fluid flow control valves shown in conjunction with an appliance;

FIG. 2 is a sectional view taken along the line A A of FIG. 1;

FIG. 3 is a modification of a portion of the assembly in FIG. 1 in which two chambers are connected to a common outlet;

FIG. 4 shows schematically a second embodiment of a valve assembly incorporating two fluid flow control valves, also shown in conjunction with an appliance;

FIG. 5 is a sectional view through a valve assembly constructed substantially in accordance with the schematic arrangement in FIG. 1;

FIG. 6 is a section along the line B B of FIG. 5;

FIG. 7 is a section along the line C C of FIG. 5 but showing an alternative arrangement of disposal ports;

FIG. 8 is a sectional view of another form of valve assembly;

FIGS. 9 and 10 are views of two alternative chamber configurations of the valve assembly of FIG. 8, seen along the line D D of FIG. 8; I

FIG. 1 l is a sectional view of yet another form of valve assembly;

FIGS. 12 15 are embodiments showing means for controlling a control valve, in sectional views corresponding to a section of FIG. 5 along the line E E;

FIG. 16 is a sectional view of a further form of valve FIG. 29 illustrates still yet another embodiment of valve member; and

FIG. 30 illustrates two arrangement to assist in the removal of a valve plate from a wall of the chamber.

In order that the operation of the valve and valve assembly is made well clear both the lay-out of the principal device (FIG. 1) and the modified lay-out (FIG. 4) are shown in conjunction with an appliance, a double acting cylinder being chosen for the first instance and a single acting cylinder for the second instance. It should however be understood that these particular applicances are examples only and that the valve assembly can also be applied otherwise.

In FIG. 1, the assembly comprises three chambers complete with plates, and ports, of which one is an Inlet Chamber 1 containing plate 2 and provided with an inlet free port 3 in a circumferential wall, each side wall containing one coverable port 4, 5 and one coverable control port 6, 7. The drawings show all chambers with parallel sidewalls and the sectional view (FIG. 2) shows the circumferential wall of the chambers to be circular, which configuration is by way of example only.

The other two chambers 8 and 9 which in the following are called the Outlet Chamber. are also provided with plates 10 and 11, one inlet free port 12 and 13 in the respective circumferential walls, one coverable port 14 and 15 on one sidewall of each cavity and one port 16 and 17 as well as one control port 18 and 19 on the opposite sidewall of each cavity, all coverable by the respective plates. The two chambers 8 and 9 are fixed in their relative position to each other in such a way that the control ports 18 and 19 are opposite each other and a pin 20, having access to the two chambers through the ports 18 and 19, can slide in sleeves 18a and 19a adjacent to the ports 18 and 19. The length of the pin is such that whilst one end thereof is in line with the sidewall of one chamber the other end thereof protrudes into the other chamber, and the arrangement being such that when one pin end touches the opposite sidewall, the pin is still slidingly guided in the sleeves.

The coverable port 14 of outlet chamber 8 is connected with with port 4 of the inlet chamber by means of a passage 21, which is provided with a bleed orifice 22, whereas the corresponding port 15 of the outlet chamber 9 is connected to the port 5 of the inlet chamber by a passage 23, also containing a bleed orifree 24. Passages 25 and 26 are connected to the ports 16 and 17 at the control port sides of the outlet chambers. They serve to dispose of the fluid from the device and can also be arranged to join into one common disposal passage 27 if so required (FIG. 3).

The free ports 12 and 13 of the outlet chambers 8, 9 are, shown as example only, connected by passages 28 and 29 to the working chambers 30, 31 of a double acting cylinder 32 with a piston 33 and piston rod 34.

The flow of fluid is switched from one outlet port 12 or 13 to the other outlet port by a force acting through the control ports 6 or 7 of the inlet chamber, through which the foil in that chamber is bodily moved from the side which it is resting on. After the plate has been forcibly moved by about half its traverse, the pressure difference developing on opposite sides of the plate creates a force strong enough to rapidly complete the movement of the foil to the other sidewall of the chamber. The switching force can be transmitted to the foil by either mechanical or fluidic means, some methods and embodiments thereof being described later on.

The operation of the assembly is as follows: Assuming that the plate 2 of the inlet chamber 1 is on that side as shown in the diagram (FIG. 1) fluid supplied through the inlet port 3 flows then through port 4, passage 21 and port 14 into output chamber 8. The pressure of the fluid moves the plate in that chamber over to the opposite sidewall, whereafter the disposal port 16 is sealed and pin 20 forcibly moved towards the opposite chamber 9. A passage is now open for the fluid to flow via outlet port 12 and passage 28 into the working chamber 30 of cylinder 32, causing the piston 33 to move in the outward direction against a force which may be applied to the piston rod 34. Whilst this is taking place the volume of the working chamber 31 on the other side of the piston decreases and the fluid thus displaced flows through passage 29 into the outlet chamber 9. The plate 1 1 of this chamber has been lifted off the sidewall of the disposal port 17 and the control port 19 by the previously described movement of the pin 20, thus opening the chamber to passage 26 via port through which any fluid leaking through port 5 of the inlet chamber 1 and port 15 of the outlet chamber 9 can drain away, thus preventing any pressure build-up.

When the piston 33 has reached its end position in the outward direction, plate 2 in the inlet chamber is switched over to the other side by I a force acting through the control port 7 thereby opening port 5 and closing port 4. This force may be effected manually or else automatically by a striker fastened to a component which is connected to the piston rod.

The flow of the fluid supplied through port 3 is now directed through port 5, passage 23 and port 15 into the outlet chamber 11, forcing the plate to move against the sidewall of control port 13 thereby closing disposal port 17 and traversing pin 20 towards the opposite outlet chamber 8, which pushes plate 10 from its seat and opens the disposal port 16. Fluid from chamber 9 now flows through passage 29 into the working chamber 31 of the cylinder 32, moving the piston 33 to the inside, and the fluid displaced from chamber 30 at the other side of the piston flows through passage 28, chamber 8 and port 16 into the passage 25 for disposal. Leakage of fluid through the ports 4 and 14 can drain off through the bleed orifice 22. Reversal of the piston movement is now a repeat of that explained in the foregoing.

A modified version of a valve assembly containing one outlet port only is obtained through elimination of one of the two outlet chambers. The lay-out of this version, thus modified, is shown, again by way of example, in conjunction with a cylinder, this time however with one working chamber only, the return stroke being effected by a spring 44 (FIG. 4). The inlet chamber 1 with plate and ports, outlet chamber 8 with plate and ports, passage 21 with bleed orifice 22 are retained from the lay-out shown in FIG. 1 but modified by a passage 35 with a bleed orifice 36 which now connects the coverable port 5 of the inlet chamber 1 with the control port 37 of the outlet chamber 8, said control port being situated at the sidewall opposite port 14 and provided with a sleeve 37a which slidingly supports a pin 38, limited in its movement away from the chamber by a stop 39. The length of the pin 38 is such that when resting against the stop its front end near the chamber is still behind the chamber sidewall, and therefore does not impede the free movement of the plate 10 against that side wall but is long enough to be securly supported when resting with its end against the opposite sidewall. Passage 28 leads from the free port 12 of the outlet chamber to the working chamber 40 of the cylinder 41, the piston 42 and rod 43 being returned by spring 44.

The piston 42 is moved to the outward direction against the force of the spring when the plate in the inlet chamber covers port 5 and opens port 4. Fluid supplied through port 3 flows through passage 21 and port 14 into the chamber 8, moving plate 10 to the opposite sidewall, thus closing disposal port 16 and moving pin 38 towards the stop 39. The flow continues via port 12 and passages 28 into the working chamber 40 of the cylinder 41, whilst leakage through ports 5 and 37 into passage 35 is drained away through the bleed orifice 36.

When the piston 42 has reached its outward end position the foil 2 of the inlet chamber is moved over to the other side wall by a force acting through the control port 7, which opens port 5 of the inlet chamber and closes port 4. The fluid can now enter passage 35 and moves the pin 38 by its pressure towards the chamber 8 and therefore also moves the plate in the chamber to the opposite sidewall. Port 14 is now closed and disposal port 16 open, so that the fluid in chamber 40, being displaced by the inward movement of piston 42 under the action of spring 44, flows via passage 28, chamber and port 16 into passage 25 for disposal from the device. Drainage of fluid leaking through ports 4 and 14 by way of the bleed orifice 22 ensures that the fluid pressure in passage 21 is below that of chamber 8.

In order to restart the outward stroke of the piston 42, plate 2 in chamber 1 is moved to the side of ports 5 and 7 by a force acting this time through the control port 6.

The following describe some practical embodiments of a valve assembly which are examples only of such assemblies having two outlet ports, the same principles being applicable to embody an assembly with a single outlet according to the lay-out described in FIG. 4. In the examples shown, the relative position of the chambers to each other or the position and directions of the passages and port holes are not limitative of the inventron.

The first embodiment shown (FIGS. 5, 6, and 7) consists of three blocks 45, 46 and 47, with parallel sides, held together by a plurality of screws or bolts 48 or by any other means. An inlet chamber 49 is formed by a hollow in the middle block whereas two outlet chambers 50 and 51 are formed by cavities on those sides of the outer blocks 47 and 48 which face the middle block 46. The outlet chambers in the outer blocks are opposite each other but off-set from the inlet chamber in the middle block so that one sidewall of each chamber is formed by the flat surface of the adjoining block. Each chamber is provided with a valve-plate 52, and a hole 53 in the middle block 46 connects the two outlet chambers and carries a pin 54 which can slide towards one or other of the chambers. The inlet chamber 49 is connected by a passage 55 to the outlet chamber 50 on one side, and by a passage 56 to outlet chamber 51 on the other side, all chamber ports being in such a position that they can be covered by the plate 52 when the latter are resting on the respective sidewalls. Each passage is provided with a bleed orifice 57 and 58. The disposal passages 59 and 60 are situated in the middle block at a place coverable by the valve plates of the outlet chambers 50 and 57 and join into one common passage 61a or, in a modified version, can also remain separate (FIG. 7 Two further ports 61 and 62 lead from the inlet chamber 49 to the outside from a place at the sidewalls which is coverable by the valve plate of that chamber. These ports are control ports and are arranged to carry means for forcibly moving the valve plate from one sidewall to the opposite one The fluid is supplied to the inlet chamber through an external port 63, situated at the outside of the inner block 46 and connected with the chamber by a passage 64 which meets the chamber on the circumferential wall at a place near the control port 61, 62 (FIG. 6). Delivery of the fluid supplied through port 63 is through the external ports 65 and 66. Port 65 is on the outside of the outer block 45 and connected to the outlet chamber 50 by a passage 67, whereas port 66 is in the other outer block 47 and connected to chamber 51 by passage 68, both passages meeting the outlet chambers in their circumferential walls at a place near the plate 52, (FIG. 7).

The disposal passage 61a terminates in an external port 69, or, if with two separate disposal passages 59 and 60, in the external ports 70 and 71. Similarly, both bleed orifices can be provided with external ports 72 and 73.

The side walls of the embodiment described in the foregoing are parallel to each other and of circular shape, but other configurations are shown in FIGS. 8, 9 and 10.

The two sidewalls 74 and 75 of a chamber in the embodiment shown in FIG. 8 include an angle, but leaving the surrounding wall 76 at the apex 77 with sufficient width to allow the valve plate 78 to move freely from one side wall to the other without wedging in at the apex. The shape of the side walls can be circular as shown at 82 of FIG. 9 or rectangular or with two parallel sides 83 (FIG. 10) connected by curved ends 84, as this may be practical for the purpose of manufacture.

Yet another embodiment of a valve according to the invention is shown in FIGS. 16 and 17. The valve chambers are formed by cylindrical filling pieces situated in two parallel bores 201, 202 in a body 203. An inlet chamber 204 is formed by the sides of filling pieces 205, 206, and two outlet chambers 207, 208 by the sides of a central piece 210 and the sides of outer pieces 209 and 21 1. End plates 212, 213 are secured to the sides of the body 203 in order to keep the filling pieces in position.

In another embodiment the device is divided into two bodies, one containing an inlet chamber 49 and the other outlet chambers 50 and 51 (FIG. 11). The inlet chamber is formed by two components 84 and 85 attached to each other by means of screws, bolts (not shown) or other means. The inlet port 63 and control ports 61 and 62 are arranged as on the examples shown previously, but the side ports 86 and 87 of the chamber now lead to external ports 88 and 89.

The second body consists of three components 88a, 89a and 90 which are attached to each other in the manner described before, the inner components 89a being a block with two parallel sides and containing a pin 54 in a hole 53 and a single external disposal port 69 or dual ports 70 and 71, of which only the former one is shown. The two outer components 88a and 90 contain, at their flat sides, outlet chambers 50, 51 and external outlet ports 65, 66 and also external ports 91, 92 with passages 93 and 94, which lead to outlet chambers 50 and 51, entering said chambers at the side walls opposite the walls formed by the middle block 89a at a place coverable by valve plates 52. The connection, by pipes 95 and 96 of the external ports 88, 89 of the body containing the inlet chamber with the ports 91 and 92 of the second body containing the outlet chambers accords with the lay-out of the device to that shown in FIG. 1, but allows mounting of the inlet chamber containing body at one place whilst it may be convenient to mount the body containing the delivery and disposal ports at another place some distance away.

Further embodiments of the invention include the integration of the whole or part of the lay-out into components of the appliance which the device is to control.

The movement of the valve plate inside the inlet chambers from one sidewall to the opposite one for the purpose of switching the fluid delivery from on port to the other is effected by a force which acts on the foil through the control ports at the side walls of the inlet chamber. There are several methods in which this can be realized and the following describes the embodiment of some methods by way of example only, shown as if applied to the device illustrated in FIG. of the drawings, FIGS. 12 15 being derived from a sectional view along a line E E of FIG. 5 showing the inlet chamber 49, with valve plate 52, external inlet port 63 and the two control ports 61 and 62, one at each of the two opposite sidewalls.

In one embodiment, two housings 97, 98 with holes 99, 100 are fastened to the outside of the outer plates 45 and 47. Slidingly supported in the holes are two plungers 101, 102 each being provided with flanges 103, 104 with a diameter larger than that of the plunger shaft, which by moving in respective enlarged recesses 105, 106 of the housings 97, 98 limit the traverse of the plunger in both directions. The position of the housings is such that the control ports 61, 62 are wholly or partly covered by the flanges of the plungers if resting against the face containing the external exits of the control ports. Two pins 107 and 108 are slidingly supported in the control ports 61, 62, the length of the pins being such that when plungers and pins are moved to their extreme outer positions the inner ends of the latter do not protrude into the chamber and therefore do not restrain the valve plate 52 from resting against the sidewalls of the chamber.

In another method, the control pins 107, 108 are moved towards the chamber through the force of fluid displaced from the remote chambers 112 or 113 (FIG. 13) by the movement of flanged plungers 114, 115 in their respective housings 116, 117 when struck by strikers 109 or 110. Two blocks 118, 119 with ports 120, 121 are attached to the sides of the external control port exits 61, 62 in such a way that fluid can flow from said ports 120, 121 into the control ports. The control pins 107 and 108 which are loosely supported in the control ports, are arrested by stoppers 122 and 123 in their outward movement. Pipes 124, 125 connect the ports 120, 121 of the blocks to the ports 126, 127 at the housings 116, 117, which may therefore be mounted in a position remote from the device.

The operation is similar to that of the previous embodiment, except that the plungers 114, 115, after being struck by the strikers, are returned outwardly by fluid flowing from the inlet chamber 49 through the clearance between the control pins and control ports into the chamber 112 and l 13 of housings l 16, l 17.

In a further embodiment the valve plate of the inlet chamber 49 is moved from one side to the other by the direct force of fluid pressure without the interaction of control pins. The force is generated when plungers 128 or 129 (FIG. 14), slidingly supported in housings 130 and 131, are struck by strikers 109 or 1 10, thus forcing the fluid contained in the recesses 132 and 133 through the control ports against the back of the valve plate 52.

In a modified version of this method (FIG. 15) the control flow is generated by the movement of plungers in housings mounted in a remote position similar to the arrangement shown in FIG. 13, or by plungers sliding in any component moving under the control of the device which when struck by stationary strikers displace fluid contained in a chamber which is directed through pipes 134, 135 to the ports 136, 137 at the exits of the control ports 61 62.

FIG. 18 differs from FIG. 1 by having two additional control ports 201 and 202 arranged in the sides of the outlet chambers 8 and 9 respectively opposite the plunger 20.

In FIG. 19 the assembly comprises an inlet chamber 1 and only one outlet chamber 8. In addition to an outlet port 12 and a disposal port 25 the chamber 8 is provided with a control port 203. In use, the control port controls the movement of the plate in the chamber 8.

FIG. 20 illustrates a valve assembly having one inlet chamber sandwiched between two outlet chambers. Control plungers 204 and 205 slidable in sleeves 206 and 207 respectively control the movement of the plate in chamber 1 from one side wall to the other and also control the movement, in one direction only, of the plates in chambers 8 and 9. The opposite direction of movement of these plates is effected through external control ports 208 and 209.

In the illustrated position of the plates, fluid enters chamber 1 through inlet 3 and flows through chamber 8 and outlet 12 to one side of a work piston (not shown). The other side of the work piston is connected to port 13 which communicates through chamber 9 with a disposal port 26. To reverse the flow of fluid, the valve plate in each of the chambers 1, 8 and 9 is switched from one wall to the opposite side wall by a force applied through control port 209. The plate in chamber 9 in moving across this chamber to uncover port 23 and cover port 26 moves the plunger 205 to the right. This in turn moves the plate in chamber 1 which through the plunger 204 moves the plate in chamber 8. To revert to the original flow direction, a control force is applied to the port 208.

The force applied to the control ports 208 and 209 can be pneumatic, hydraulic or mechanical.

FIG. 21 illustrates another form of two chamber assembly. A plunger 210, slidable in sleeve 211, is disposed between the inlet and outlet chambers. A first control port 212 communicates with one side of the chamber 1 and a second control port 213 communicates with one side of chamber-8. A control force in port 213 switches the plate in chamber 8 to the opposite side wall thereof to cover port 25 and simultaneously the plate, by way of the plunger 210, moves the plate in chamber 1 to cover the control port 212. Fluid can then flow from the chamber 1 to chamber 8 and thence through port 12 to a work member. Upon applying a control force to port 212 the assembly reverts to its illustrated position.

FIG. 22 illustrates an arrangement of three chambers similar to that shown in FIG. 20 with the exception that the outlets 214 and 215 from chamber 1 do not lead directly to the chambers 8 and 9 respectively. FIG. 23 shows a modified arrangement of the chambers where again the outlets from chamber 1 do not lead directly to the chambers 8 and 9. In both FIGS. 22 and 23 fluid flowing through chamber 1 passes directly to a work member without flowing through chambers 8 and 9. Otherwise, this arrangement operates in the same way as that in FIG. 20.

In FIG. 24 a plunger 210 slidable in sleeve 211 is disposed between the two chambers l and 8. This arrangement is similar to that in FIG. 21 with the exception that the outlet 216 from chamber 1 communicates directly with the port 12 and does not enter the chamber 8.

FIGS. 25a, 25b and 25c are schematic illustrations of an alternative mode of operation of the valve.

With fluid flowing through the valve as indicated by the arrows in FIG. 25a, the plate or foil can be switched to close port 222 and open port 223 by closing or blocking the open end of port 223. This is shown in FIG. 25b in which the port 223 has been closed by a member 224 and the plate or foil has moved across the chamber to close port 222. No fluid can now pass through the valve until the member 224 is removed when fluid again flows as indicated by the arrows in FIG. 25c.

The transport of the plate or foil between opposite walls of the chamber is a result of the static fluid pressure developing between the external closure member 224 and the layer of fluid between the foil and the wall, this pressure being higher than the pressure of the flowing fluid acting on the other side of the wall.

FIG. 26 illustrates one example of a valve incorporating this mode of operation. Inlet chamber 225 contains a plate or foil 226 movable across the chamber to close outlet ports 228 and 229. Fluid inlet port 227 remains open at all times and is not covered by the plate or foil. The ends of the ports 228 and 229 remote from the chamber 225 communicate with chambers 228a and 229a respectively in which are slidable the heads of plungers 230 and 231. The chambers 228a and 229a have respective outlets 232 and 233 to couple the valve member to a work member.

In the position of the foil or plate 226 illustrated in FIG. 26, fluid entering the inlet 227 leaves the valve member through outlet 232. Upon moving plunger 231 to the right to close port 229, the foil 226 moves across the chamber 225 to cover port 228 and output through port 232 is cut off. Upon withdrawing the plunger 231 fluid can now flow through the valve member to leave at outlet 233. Similarly, operation of the plunger 230 will return the valve to the illustrated position.

The valve member in FIG. 26 can replace the inlet chambers of the valve members disclosed in earlier figures. The plungers 230 and 231 can be operated manually or by mechanical, electrical, pneumatic or hydraulic means.

In FIG. 26 the flow of fluid is completely shut off as long as the respective plunger is maintained in contact with the outlet port. It is desirable to maintain the force required to hold the plunger in engagement with the outlet port as small as possible when the valve is used as a shut-off valve and this can be achieved as shown in FIG. 27 by reducing the diameter of one of the two outlets so that it becomes an orifice. The orifice allows leakage from the region between the wall and foil to bleed off so that pressure build-up in this region, which could cause switching of the plate, is prevented.

In FIG. 27, a shut-off plunger is denoted by numeral 235 and the outlet port 236 is closed by the foil. The valve is opened by withdrawing the plunger 235 to open the orifice 234 and by momentarily closing the output port 236 in a manner as described with reference to FIG. 26 or by direct action on the foil through a control port 237. Such a valve member can replace the valve member disclosed in the accompanying FIGS. 19, 21 and 24. To return the foil back to the illustrated position it is merely necessary to advance the plunger 235 to close the orifice 234.

FIG. 28 illustrates a valve member having two plates or foils. Chamber 241 is formed with an inlet port 242, an outlet port 244 and control port 246 in one side wall, and an outlet port 243 and control port 245 in the opposite side wall. Two plates or foils 247 and 248 are accommodated in the chamber 241, the plates or foils being controlled by control plungers 249 and 250 located in the control ports 245 and 246 respectively.

FIGS. 28a and 280 illustrate two fluid flow paths through the valve.

In FIG. 28a, when the plunger 250 is withdrawn the plate 248 returns to its position against the side wall to close outlet port 244. Both outlet ports are then closed as in FIG. 28b. Lifting the other foil 247 by the plunger 249 will allow fluid to flow through the outlet port 243.

When lifted off the walls the pressure between the foils is greater than the pressure on the flow side of a foil and the foil is maintained in a position away from a side wall by the appropriate plunger. On withdrawal of the plunger, the foil returns against the chamber wall under the influence of the pressure acting between the two foils.

The valve member in FIG. 28 thus has four operative states, namely, output through port 243 only; output through port 244 only; and no output with both ports closed and output through both ports 243 and 244 when both of these ports are open.

It will be appreciated that the valve members in the arrangements disclosed in earlier figures can be provided with two plates or foils.

In FIG. 29, the valve chamber 251 has one inlet port 252, one outlet port 253, one control port 254 and one plate 255. Fluid flows through the valve as long as the plate 255 is held away from the outlet port 253 by the plunger 256. When the plunger is withdrawn into the position shown in FIG. 29, the plate 255 closes the outlet port 253 as a result of the pressure difference between the flow side of the foil and the region between the foil and the wall of the chamber opposite to the ported wall.

FIG. 30 illustrates examples of the manner in which the force required to move the foils away from the walls of the chamber can be reduced.

Foil 261 is such that when the plunger 262 is advanced into the chamber it first deflects end 263 of the foil to create a small gap between the foil end and the wall of the chamber. Fluid from the chamber enters this gap so as to balance the hydrostatic forces on opposite sides of the foil. On further advance of the plunger the balanced areas on opposite sides of the foil are increased and the foil can therefore be peeled away from the wall. The foil is of such a flexible material that it will be progressively peeled away from the chamber wall as the plunger is advanced into the chamber.

As an alternative method, a recess may be formed at the rear of the foil adjacent the control port. This recess 264 as shown in FIG. 30 communicates with the interior of the chamber and thus the pressure over the front and rear faces of the foil in the region of the control plunger are equal.

We claim:

1. A fluid flow valve assembly comprising a first fluid flow control valve having a housing, a chamber in said housing, an inlet port in communication with said chamber, at least one outlet port from the chamber, a valve member in the form of at least one plate in the chamber, said plate being free from permanent connection with any other parts and movable to prevent flow through said at least one outlet port, said inlet port being at least partially unobstructed in all positions of said valve member, means for controlling the movement of said valve member,. and a second fluid flow control valve comprising a housing having a chamber therein? a movable -member in the third chamber being movable between a first position in which the entry port communicates with the further port and communication between the tTrtherportand the outlet port of the third valve is prevented and a second position in which communicaadiseitven'aienay port and the further port is obstructed and the outlet port of the third valve communicates with the further port.

i A valveassembly according to claim 7 wherein the outlet ports of said second and third control valves are connected to a common outlet.

9. A valve assembly as claimed in claim 7 wherein said first second and third control valves are secured together to form an integral body.

from permanent connection with any other parts,:

an entry port in a wall of said chamber and communicating with the said at least one outlet from the first valve, an outlet port in an opposed wall of the chamber of said second control valve, and a further port in communication with said chamber of said second valve positioned so as to be at least partially unobstructed in all positions of the valve member, the valve member of the second valve being movable between a first position in which the entry port communicates with the further port and communication between the further port and the outlet port is prevented and a secoiid flsitiefi ifilfielii communication between the entry port and the further port is obstructed and the outlet port communicates with the further port.

2. A fluid newedn'tiarvaiveassefisiy aeco rdi ng to claim 1 wherein the chamber of the first valve is a cylindrical cavity with opposed parallel flat walls and the valve member is a disc.

3. A fluid flow control valve assembly according to claim 1 where in at least one chamber isof wedgeshaped cross-section with flat circular walls in intersecting planes and at least one valve member is a disc.

4. A fluid flow control valve assembly according to claim 1 wherein at least one chamber is of wedgeshaped cross-section, the opposed walls being shaped with two parallel sides connected by curved ends, its respective valve member being of the same shape.

5. A fluid flow control valve assembly according to claim 1 wherein two outlet ports lead from the first chamber with one outlet port in each of opposed side walls of the chamber of the first valve.

6. A fluid flow control valve assembly according to claim 5 wherein a plunger is co-operable with each outlet port to selectively open and close said port to switch the first valve member between said opposed walls of the first chamber.

7. A fluid flow valve assembly as claimed in claim 5, a third fluid flow control valve comprising a housing having a chamber therein. a movable valve member in the form of a plate in said chamber of the third valve, said plate being free from permanent connection with. any other parts, an entry port in a wall of said third chamber and communicating with an outlet from said 10. A v a l ve assembly according to claim 9 wherein the first control valve is located between the second and third control valves.

ll. valve assembly according to claim 7 wherein the first control valve is remote from the second and third control valves, which latter valves are secured together to form an integral body.

\ 12. A valve assembly according to claim 7 wherein the outlets from said first valve communicate directly with said further port in said respective second and third control valves.

13. A valve assembly according to claim 7 wherein said plunger is operated by fluid pressure.

14. A fluid flow valve assembly according to claim 7 wherein said bore is so located that said plunger engages each of said second and third valve members at a point spaced from the center of each of said valve members.

15. A fluid flow control valve assembly according to claim 1 including control means comprising two plungers each slidable in a bore communicating with one of said opposed walls of the first chamber.

16. A fluid flow control valve assembly according to claim 1 wherein at least one valve member comprises a pair of plates disposed in its respective chamber.

17. A fluid flow control valve assembly according to claim 1 wherein each plate is formed from a flexible material whereby the plate can be progressively peeled away from contact with a wall of its respective chamber.

18. A fluid flow control valve assembly according to claim 1 wherein a recess is formed in each of the opposed walls of one of the chambers at a region remote from an outlet, said recess being in communication with the chamber whereby to equalize pressures acting on opposite faces of the valve member in the vicinity of said region.

19. A valve assembly according to claim I wherein said first and second valves are arranged side by side in a common housing.

20. A valve assembly according to claim I) wherein an outlet from the first valve communicate directly with said further port of the second valve.

21. A fluid flow control valve assembly according to claim 1, comprising control means communicating with with the chamber of the second valve comprises a plunger reciprocable in a bore connecting said chamber to an outlet of the chamber of the first valve. 

1. A fluid flow valve assembly comprising a first fluid flow control valve having a housing, a chamber in said housing, an inlet port leading into said chamber, at least one outlet port from the chamber, a valve member in the form of at least one plate in the chamber, said plate being free from permanent connection with any other parts and movable to obstruct said at least one outlet port, said inlet port being unobstructed in all positions of said valve member, means for controlling the movement of said valve member, and a second fluid flow control valve comprising a housing having a chamber therein, a movable valve member in the form of a plate in the chamber of said second control valve, said plate being free from permanent connection with any other parts, an entry port in a wall of said chamber and communicating with the said at least one outlet from the first valve, an outlet port in an opposed wall of the chamber of said second control valve, and a further port in said chamber of said second valve positioned so as not to be obstructed by the valve member, the valve member of the seconD valve being movable between a first position in which the entry port communicates with the further port and communication between the further port and the outlet port is obstructed and a second position in which communication between the entry port and the further port is obstructed and the outlet port communicates with the further port.
 2. A fluid flow control valve assembly according to claim 1 wherein the chamber of the first valve is a cylindrical cavity with opposed parallel flat walls and the valve member is a disc.
 3. A fluid flow control valve assembly according to claim 1 where in at least one chamber is of wedge-shaped cross-section with flat circular walls in intersecting planes and at least one valve member is a disc.
 4. A fluid flow control valve assembly according to claim 1 wherein at least one chamber is of wedge-shaped cross-section, the opposed walls being shaped with two parallel sides connected by curved ends, its respective valve member being of the same shape.
 5. A fluid flow control valve assembly according to claim 1 wherein two outlet ports lead from the first chamber with one outlet port in each of opposed side walls of the chamber of the first valve.
 6. A fluid flow control valve assembly according to claim 5 wherein a plunger is co-operable with each outlet port to selectively open and close said port to switch the first valve member between said opposed walls of the first chamber.
 7. A fluid flow valve assembly as claimed in claim 5, a third fluid flow control valve comprising a housing having a chamber therein, a movable valve member in the form of a plate in said chamber of the third valve, said plate being free from permanent connection with any other parts, an entry port in a wall of said third chamber and communicating with an outlet from said first control valve, an outlet port in an opposed wall of the third chamber and a further port communicating with the third chamber so as not to be obstructed by the valve member therein, and a plunger movable in a bore between the chambers of said second and third control valves to protrude alternately into one of the chambers to actuate the respective valve members, the valve member in the third chamber being movable between a first position in which the entry port communicates with the further port and communication between the further port and the outlet port of the third valve is obstructed and a second position in which communication between the entry port and the further port is obstructed and the outlet port of the third valve communicates with the further port.
 8. A valve assembly according to claim 7 wherein the outlet ports of said second and third control valves are connected to a common outlet.
 9. A valve assembly as claimed in claim 7 wherein said first second and third control valves are secured together to form an integral body.
 10. A valve assembly according to claim 9 wherein the first control valve is located between the second and third control valves.
 11. A valve assembly according to claim 7 wherein the first control valve is remote from the second and third control valves, which latter valves are secured together to form an integral body.
 12. A valve assembly according to claim 7 wherein the outlets from said first valve communicate directly with said further port in said respective second and third control valves.
 13. A valve assembly according to claim 7 wherein said plunger is operated by fluid pressure.
 14. A fluid flow valve assembly according to claim 7 wherein said bore is so located that said plunger engages each of said second and third valve members at a point spaced from the center of each of said valve members.
 15. A fluid flow control valve assembly according to claim 1 including control means comprising two plungers each slidable in a bore communicating with one of said opposed walls of the first chamber.
 16. A fluid flow control valve assembly according to claim 1 wherein at least one valve member compriSes a pair of plates disposed in its respective chamber.
 17. A fluid flow control valve assembly according to claim 1 wherein each plate is formed from a flexible material whereby the plate can be progressively peeled away from contact with a wall of its respective chamber.
 18. A fluid flow control valve assembly according to claim 1 wherein a recess is formed in each of the opposed walls of one of the chambers at a region remote from an outlet, said recess being in communication with the chamber whereby to equalize pressures acting on opposite faces of the valve member in the vicinity of said region.
 19. A valve assembly according to claim 1 wherein said first and second valves are arranged side by side in a common housing.
 20. A valve assembly according to claim 19 wherein an outlet from the first valve communicates directly with said further port of the second valve.
 21. A fluid flow control valve assembly according to claim 1, comprising control means communicating with the chamber of the second valve to actuate the valve member therein.
 22. A fluid flow control valve assembly according to claim 21 wherein said control means communicating with the chamber of the second valve comprises a plunger reciprocable in a bore connecting said chamber to an outlet of the chamber of the first valve. 